Geochemistry and petrology of the Harsin-Sahneh ophiolitic complex (NE Kermanshah-West of Iran): Implication for the tectonic of Southern Neo-Tethys

Abstract

Ophiolites of the Zagros orogenic belt are part of the Tethys ophiolites, because of their geographical locations and link the Middle East ophiolites and other Asian ophiolites (e.g. Pakistani and Tibetan) to the Mediterranean ophiolites (e.g. Troodos , Greek and East European). The nature of the Harsin- Sahneh ophiolite (Kermanshah) traditionally identified as one of the Mesozoic southern branch of the Neo-Tethys Ocean and remnants of the Peri- Arabic ophiolite system obducted onto Arabian shield (Gondwana) that is reinvestigated in this study. Petrographic evidence indicates that this ophiolitic sequence consists of both mantle and crustal suites. In generals lithologies in this complex include harzburgitic and lherzolitic peridotites, cumulate, pegmatoidic and mylonitic gabbros, dyke complex and basaltic pillow lavas. Mineral chemisty of Harsin mafic rocks indicating island arc setting for this part of complex and geochemistry of mafic and ultramafic rocks of Sahneh region displaying P-type MORB nature. Presence of basalts with different composition in this region can be interpreted as the interaction between MORB-type and OIA-type asthenosphere.  Field relationships and geochemical evidence indicate that involved ophiolites were part of a rifted basin at the ocean-continent transition zone, which formed in the south of the Neo-Tethyan Ocean. The break-off of Neo-Tethyan slab and subduction of this slab branch itself during Cretaceous led to cessation of Neo-Tethyan subduction branch Sanandaj-Sirjan block, and forming arc-back arc basin and related rocks in the Kermanshah ophiolite and MORB magmatism occurred in response to slab retreat in the Eurasian continental margin.

Keywords


[1] Agard P., Omrani J., Jolivet L.,Whitechurch H., Vrielynck B., Spakman W., Monie P., Meyer B., Wortel R., "Zagros orogeny:a subduction-dominated process", Geological Magazine 148)2011( 692–725.

[2] Allahyari K., Saccani E., Pourmoafi M., Beccaluva L., Masoudi F., "Petrology of mantle peridotites and intrusive mafic rocks from the Kermanshah ophiolitic complex(Zagros belt, Iran): implications for the geodynamic evolution of the Neo-Tethyan oceanic branch between Arabia and Iran", Ofioliti 35 )2010( 71–90.

[3] Hassanzadeh J., Stockli D.F., Horton B.K., Axen G.J., Stockli L.D., Grove M., Schmitt A., Walker J.D., "U–Pb zircon geochronology of upper Neoproterozoic–Early Cambrian granitoids in Iran: Implications for paleogeography, metallogeny, and exhumation history of Iranian basement", Tectonophysics 451)2008 (71–96.

[4] Azizi H., Moinevaziri H., "Review of the tectonic setting of Cretaceous to Quaternary volcanism in northwestern Iran", J. Geodyn. 47) 2009(167–179.

[5] Mohajjel M., Fergusson C.L., Sahandi M.R., "Cretaceous–Tertiary convergence and continental collision, Sanandaj–Sirjan Zone, western Iran", J. Asian Earth Sci. 21(2003)397–412.

[6] Alirezaei S., Hassanzadeh J., "Geochemistry and zircon geochronology of the Permian A-type Hasanrobat granite, Sanandaj–Sirjan belt: A new record of the Gondwana break-up in Iran", Lithos, 151. (2012) 122-134.

[7] Robertson A.H.F., Parlak O., Rízaoğlu T., Ünlügenç Ü., İnan N., Tasli K., Ustaömer T., "Tectonic evolution of the South Tethyan ocean: evidence from the Eastern Taurus Mountains (Elaziğ region, SE Turkey)", Geological Society, London, Special Publications 272 (2007) 231–270.

[8] Hassanipak A.A., Ghazi A.M., "Petrology, geochemistry and tectonic setting of the Khoy ophiolite,northwest Iran: implications for Tethyan tectonics", J.Asian Earth Sci.18(2000)109–121.

[9] Khalatbari-Jafari M., Juteau T., Bellon H., Whitechurch H., Cotton J., Emami H., "New geological and geochronological investigations on Khoy ophiolites and related formations. NW Iran", Journal of Asian Earth Sciences 23(2004)507–535.

[10] Azizi H., Chung S., Tanaka T., Asahara Y., "Isotopic dating of the Khoy metamorphic complex (KMC), northwestern Iran: A significant revision of the formation age and magma source", Precambrian Research 185(2011)87–94.

[11] Shahabpour J., "Island-arc affinity of the Central Iranian Volcanic Belt", Journal of Asian Earth Sciences 30(2007)652–665.

[12] Ghasemi A., Talbot C.J., "A new tectonic scenario for the Sanandaj–Sirjan Zone (Iran)", J. Asian Earth Sci. 26(2006) 683–693.

[13] Gharib F., "Biostratigraphie des radiolarites de Kermanshah (Iran)", Unpublished doctoral dissertation, Museum Nationald’Histoire Naturelle –Paris (2009) 343 p.

[14] Delaloye M., Desmons J., "Ophiolites andmelange terranes in Iran: a geochronological study and its paleotectonic implications", Tectonophysics 68(1980)83–111.

[15] Whitechurch H., Omrani J., Agard P., Humbert F., Montigny R., Jolivet L., "Evidence for Paleocene–Eocene evolution of the foot of the Eurasian margin (Kermanshah ophiolite, SW Iran) from back-arc to arc: Implications for regional geodynamics and obduction", Lithos 182–183(2013)11–32.

[16] Wrobel-Daveau J.C., Ringenbach J.C., Tavakoli S., Ruiz G., Masse P., Frizonde Lamotte D., "Evidence for mantle exhumation along the Arabian margin in the Zagros (Kermanshah area, Iran)", Arabian Journal of Geosciences.Springer 3(2010) 499–513.

[17] Saccani E., Allahyari K., Beccaluva L., Bianchini G., "Geochemistry and petrology of the Kermanshah ophiolites(Iran):implication for the interaction between passive rifting,oceanic accretion and OIB-type components in the Southern Neo-Tethys Ocean", Gondwana Research 24 (1), (2013) 392–411.

[18] Allahyari K., Saccani E., Rahimzadeh B., Zeda O., "Mineral chemistry and petrology of highly magnesian ultramafic cumulates from the Sarve-Abad (Sawlava) ophiolites (Kurdistan, NW Iran): New evidence for boninitic magmatism in intra-oceanic fore-arc setting in the Neo-Tethys between Arabia and Iran", Journal of Asian Earth Sciences 79 (2014)312–328.

[19] Nicolas A., Boudier F., Bouchez J.L., "Interpretation of peridotite structures from ophiolitic and oceanic environments, American Journ.of Sciences, 28O A(1980) 192–210.

[20] Pearce J.A., Norry M.J., "Petrogenetic implications of Ti, Zr, Y, and Nb variations in volcanic rocks", Contrib. Mineral.Petrol., 69(1979)33-47.

[21] Parlak O., Ho¨ck V., Delaloye M., "The supra-subduction zone Pozanti–Karsanti ophiolite, southern Turkey: evidence for high-pressure crystal fractionation of ultramafic cumulates", Lithos 65 (2002) 205-224.

[22] Nisbet E.G., Pearce J. A., "Clinopyroxene composition in mafic lavas from different tectonic settings", Contribution to Mineralogy and Petrology 63 (1977) 149-160.

[23] Jensen L. S., "A New Cation Plot for Classifying Subalkalic Volcanic Rocks", Ontario Geological Survey Miscellaneous, (1976). pp 66.

[24] Pearce T. H., Gorman B. E., Birkett T. C., "The relationship between major element geochemistry and tectonic environment of basic and intermediate volcanic rocks", Earth and Planetary Science Letters 36(1977)121–132.

[25] Gioncada A., Mazzuoli R., Bisson M., Pareschi M T., "Petrology of volcanic products younger than 42 ka on the Lipari-Vulcano complex (Aeolian Islands, Italy): an example of volcanism controlled by tectonics", Journal Volcanology Geotherm. Research. 122 (2003) 191-220.

[26] Reilinger R., McClusky S., "Nubia–Arabia–Eurasia platemotions and the dynamics of Mediterranean and Middle East tectonics, Geophysical Journal International 186 (2011)971–979.

[27] Vergés J., Saura E., Casciello E., Fernàndez M., Villaseñor A., Jiménez-Munt I., García-Castellanos D., "Crustal-scale cross-section across the NW Zagros Belt: implications for the Arabian Margin reconstruction, In: Lacombe, O., Grasemann, B., Simpson, G. (Eds.), Geodynamic Evolution of the Zagros", Geological Magazine, 148, (2011b) 739–761 (5–6).

[28] Faccenna C., Bellier O., Martinod J., Piromallo C., Regard V., "Slab detachment beneath eastern Anatolia: a possible cause for the formation of the North Anatolian fault", Earth and Planetary Science Letters 242 (1–2) (2006)85–97.

[29] Omrani J., Agard P., Whitechurch H., Benoit M., Prouteau G., Jolivet L., "Arc magmatism and subduction history beneath Zagros: new report of adakites and geodynamic consequences", Lithos 106:3–4 (2008) 380–398.

[30] Mouthereau F., Lacombe O., Vergés J., "Building the Zagros collisional orogen:timing, strain distribution and the dynamics of Arabia/Eurasia plate convergence, Tectonophysics 532-5(2012) 27–60.